Robert Redford thought someone was pulling his leg the first time he met horse trainer Dan "Buck" Brannaman. Interviewing to serve as a consultant for Redford's 1998 film adaptation of The Horse Whisperer, Buck strolled into the filmmaker's Hollywood office clad as an apparent cowboy caricature, complete with buckskin chaps and a rancher's hat.

It's an initial reaction shared by viewers of Buck, a debut documentary by Cindy Meehl about the renowned real-life "horse whisperer." The film's opening scenes show Buck and his horse galloping and cantering in slow motion through sunlit pastures while the horseman muses via voice-over how one's horse "is a mirror to your soul." Viewers may recoil slightly, finding this man too good to be true, and wonder if this is an infomercial hawking Buck's instructional videos.

The confusion has some merit. Beyond his acumen in the philosophy of "natural horsemanship," Buck is a showman, beginning at age 6, when he and his older brother Bill ("Smokie") were raised by their domineering father to be famous, record-holding trick ropers. However, any misgivings evaporate the first time you witness one of Buck's horse clinics, when he take the reins of an unbroken steed trying to buck free from its owner and, within minutes, casually guides the horse around the corral like a pied piper for equines.

And, like Redford, it's only once we get to know the life story of the soft-spoken, sometimes taciturn Buck that we appreciate the grace of the man. Deservedly the winner of audience awards at this year's Sundance and Full Frame festivals, Buck is more than a mere hagiography.

Buck's empathetic brand of horse training has its roots in the merciless physical and emotional abuse his alcoholic father heaped upon Buck and Smokie as children, particularly after the early death of their caring mother. The welts on Buck's back eventually caught the attention of a school coach and local sheriff's deputy, leading to his placement in the large, nurturing home of foster parents Forrest and Betsy Shirley.

Buck is a portrait of contrasts, the archetypal American cowboy who also carries an iPod and admits to watching Oprah for tips on what women like (according to an episode Buck mentions, a man using a vacuum cleaner is an aphrodisiac). He's the silhouette of masculinity cast against a rugged profession, but he's also a sensitive, damaged soul whose career path stems, in part, from a lifelong search for a father figure.

Vintage footage of horses being "broken" through whipping and other violent means transition to images of Buck's TLC methods, which involve little flags that he purposefully flickers in front of them. In a similar vein, although Buck's troubled childhood lends necessary context to his life and technique, Meehl refrains from flogging the audience by turning his life into a sentimental recovery narrative. There is inherent loneliness and detachment in the fact that Buck's career keeps him from his family 40 weeks out of every year. But his marriage remains resilient, and one daughter joins him on the road during summers and is following in her father's footsteps as a roper.

There are gaps in Meehl's rendering, most notably the fate of Smokie, who did not participate in the film for reasons the director curiously declined to clarify during a Full Frame post-screening Q-and-A session. Moreover, a latent push to deify Buck also persists throughout the film, making a sequence involving a brain-damaged stallion all the more important. Meehl's camera catches the horse suddenly and viciously attacking its handler during a clinic, violence that merely hints at the mistreatment it has endured. Buck's characteristically calm countenance cracks with disgust and dejection as he chastises the horse's owner for her misguided rearing. "The horse didn't fail us. We failed him," he laments.

It's not exactly throwing the money changers out of the temple, but the moment does show what makes Buck tick ... and ticked off. To paraphrase its star, Buck is not a movie about "horse problems." It's a movie about "people problems."